A study conducted by Northwestern University shows that coupling a magnetic resonance imaging (MRI) contrast agent to a nanodiamond can enhanced signal intensity and thus vivid image contrast.

The study was led by Meade with Dean Ho, assistant professor of biomedical engineering and mechanical engineering in the McCormick School of Engineering and Applied Science.

In the study Mr Ho demonstrated that the nanodiamonds have excellent biocompatibility and can be used for efficient drug delivery. This new work paves the way for the clinical use of nanodiamonds to both deliver therapeutics and remotely track the activity and location of the drugs.

The study was published online by the journal Nano Letters, is reportedly the first published report of nanodiamonds being imaged by MRI technology. The ability to image nanodiamonds in vivo would be useful in biological studies where long-term cellular fate mapping is critical, such as tracking beta islet cells or tracking stem cells.

Meade, Ho and their colleagues have also developed a gadolinium(III)-nanodiamond complex that, in a series of tests, have demonstrated a significant increase in relaxivity and, in turn, a significant increase in contrast enhancement. The Gd(III)-nanodiamond complex demonstrated a greater than 10-fold increase in relaxivity – among the highest per Gd(III) values reported to date.

The study demonstrated that the intense signal of the Gd(III)-nanodiamond complex was brightest when the Gd(III) level was highest.

The biocompatibility of the Gd(III)-nanodiamond complex underscores its clinical relevance. In addition to confirming the improved signal produced by the hybrid, the researchers conducted toxicity studies using fibroblasts and HeLa cells as biological testbeds.

They found little impact of the hybrid complex on cellular viability, affirming the complex’s inherent safety and positioning it as a clinically significant nanomaterial.

The researchers are exploring the pre-clinical application of the MRI contrast agent-nanodiamond hybrid in various animal models. With an eye towards optimizing this novel hybrid material, they will continue studies of the structure of the Gd(III)-nanodiamond complex to learn how it governs increased relaxivity.

The Nano Letters paper was titled ‘Gd(III)-Nanodiamond Conjugates for MRI Contrast Enhancement’.